The Coulombi Egg Oil Tanker 
Better protection, safer and more economical than Double Hull


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Start page
The Secret
IMO approval
General arrangement and structure
Collision protection
Grounding protection
Pirates and Terrorists
M/T Erika
The magic Egg
USCG approval
US Congress
US DoT Study 2012
M/T Limburg
M/T Prestige

  The COULOMBI EGG oil tanker design is the only alternative to Double Hull tankers approved by the IMO in accordance with Marpol I/13F(5) since 1997. It was developed 1990-1997 by Anders Björkman, Heiwa Co and it's superior environmental protection and tanker safety are adapted according to damage statistics to minimize all known risks.

  Strangely enough - since its approval by the IMO in 1997 and after mutiple tanker accidents with costly oil spills, losses of lives and damages 1997-2018, no national administrations responsible to protect the marine environment, no non-governmental organisations to protect the environment and no oil tanker industry organisations ... actually nobody ... have during 21 years ever contacted Heiwa Co about further developing safer oil tankers and safer oil transportation at sea. Strange? Is nobody in the world interested in safety of oil transportation at sea?

The COULOMBI EGG tanker spills much less oil in collision and grounding accidents than the IMO/USCG/OPA 90 Double Hull tanker designs based on the IMO data base selection of representative incidents. Actually it does not matter what data base you use. The COULOMBI EGG tanker does not spill any oil in the large majority of high energy accidents and no oil at all in low energy accidents.

  Sadly, since 1997 there has been numerous tanker accidents with single and double hull but everybody concerned has ignored the COULOMBI EGG tanker. Everybody has either concentrated on getting as much money as possible from the polluter, e.g. the poor tanker master, or has avoided by all means to avoid paying a penny to clean up the mess.

Not one penny has been used to reconfirm the IMO decision 1997, e.g. that the COULOMBI EGG tanker is much better than double hull, etc. Strange?

Well, you get the impression that the responsible parties do not care one way or another. The US Congress has adopted laws to the effect that first - a COULOMBI EGG tanker (or any IMO approved alternative but the Egg is the only one) cannot trade to the US and second - that the USCG shall evaluate alternative designs to the US OPA double hull. But the USCG has never evaluated the COULOMBI EGG - only told the Congress that the COULOMBI EGG may spill oil. Without having done a proper evaluation!

 Oil spills due to structural failures and fire/explosions were not considered by the USCG/IMO, when mandating double hull 1990/1992. Single hull tankers are apt to fracture due to corrosion and fatigue due to age and thus spill oil (e.g. the Erika, Kristin, Castor, Prestige, etc.). Double hull tankers are even more apt to fracture as the double hull is thinner steel and higher stressed structure and will start spilling oils at a younger age than single hull. Future and correct accident investigations of oil tanker accidents will prove this.

  The COULOMBI EGG tanker is much more robust than both single or double hull due to its two tiers midheight deck structure and is much more easy to inspect and maintain. The safety is increased at reduced cost. Therefore it is the only tanker design for the 21st century.

The Secret - Read about the secret of the COULOMBI EGG.

IMO Approval - The IMO approval was given by the MEPC 40th Session 18-25 September 1997 and is described in MEPC circular letter no. 336. Heiwa Co was grateful to the Swedish Maritime Administration (Roger Sundström) that sponsored the application to the IMO and to the Egyptian administration that also assisted. No other design has for twenty years been presented to the IMO to outperform the COULOMBI EGG tanker and the much inferior Double Hull standard. It is clear evidence that the COULOMBI EGG tanker is the best design. Only the USA/USCG strangely disapproves of the COULOMBI EGG tanker since 20 years. No scientific reason has ever been given.

USCG Approval - The COULOMBI EGG tanker may however any time be approved by the USCG! It is very simple! The USCG must only follow the recommendations of the 11-member Committee on Evaluating Double Hull Tanker Design Alternatives convened by the National Research Council's (NRC) under the auspices of the Marine Board. The Coast Guard Authorization Act of 1998 mandated the Secretary of Transportation to commission the Marine Board of the NRC's Transportation Research Board (TRB) to develop a rationally based approach and method for assessing the environmental performance of alternative tanker designs relative to the double-hull standard. It has now been done - the committee report is reviewed and the recommendations are very favourable for the COULOMBI EGG tanker. However the USCG does not follow up the recommendations and, e.g. no US university has shown any interest to apply the principles to the COULOMBI EGG.

General Arrangement and Structure - The COULOMBI EGG tanker uses conventional single hull construction and an innovative interior structure to reduce oil spills in collisions and groundings (and also in explosions and due to structural failures). The total amount of oil spills compared with double hull is reduced 3-4 times. As Double Hull spills very little in collision and grounding accidents, the COULOMBI EGG protection reduces total oil spills to virtually nothing. The reason for this is that the COULOMBI EGG was developed to be adapted according to actual damage statistics.

Operations - The COULOMBI EGG tanker is operated as a single hull tanker. Read about cargo operations and leaks, explosions and fires on tankers and how the COULOMBI EGG reduces the associated risks.

Collision Protection - Collision damage is more frequent, deeper and longer above waterline and in the upper side and the COULOMBI EGG collision protection - structure and a deformation zone - is located there: top side ballast tanks. Collisions with tankers are often followed by fire and explosions and loss of human life, so Heiwa Co considers that collision protection is more important than grounding protection, where few human lives are lost. The collision protection is also arranged to reduce the risk of oil spill due to strctural failures.

The magic Egg - See why the COULOMBI EGG does not spill oil in collision even if the side cargo tank is breached (a little) at its top or if there is a structural fracture in the side shell.

Grounding Protection - The simplest grounding protection is evidently hydrostatic loading of single hull cargo bottom tanks. The COULOMBI EGG improves on that, i.e. the outside hydrostatic pressure exceeds considerably the internal cargo oil pressure, so that cargo oil can be pressed up into the undamaged ballast tanks under controlled conditions in the event of grounding. The COULOMBI EGG tanker does not spill oil in a grounding.

Safety - The main reason to use the COULOMBI EGG tanker protection system is SAFETY. There are no void double hull compartments (except a longitudinal cofferdam in the sides), so there are no safety problems associated with them - internal leaks, ventilation and cleaning of double hull cells, corrosion, cleaning, etc. When the COULOMBI EGG is in loaded condition, all ballast tanks are easily accessible for inspection.

Alien Species - Ballast Water Management - The IMO resolution A.868(20) about ballast water management does not foresee that water ballast carried above the waterline can be discharged by gravity. The COULOMBI EGG tanker carries all its water ballast above the waterline (and is the only tanker or ship to do so). Removal of sediment (if necessary), etc. is very simple: you just flush it out through the side shell sea valves! Ballast water exchange to fulfill the IMO resolution A.868(20) is therefore extremely simple for a COULOMBI EGG tanker. Either you empty the topsides tanks at sea and replace the water, or, you continuously discharge the ballast by gravity during the whole voyage while simultaneously top-up ballast via the deck lines. Therefore the COULOMBI EGG tanker also simply solves the problems to prevent transport of aquatic organisms from one part of the world to another, a problem that the IMO seeks to address.

Economy - The simplest reason to use COULOMBI EGG tanker protection is money. The COULOMBI EGG costs less to build and to maintain than Double Hull as there is less structure and a weight saving, even if the deck and bottom plates are thicker than Double Hull, fewer penetrations of stiffeners, less welding and a 70% reduction in surface area in the ballast spaces. There is also less cargo piping.

M/T Erika/M/T Baltic Carrier - M/T Prestige - The COULOMBI EGG arrangement may have prevented the M/T Erika accident 1999 and the M/T Baltic Carrier collision spill 2001 and the M/T Prestige accident 2002.

The VLCC Limburg accident 6 October 2002 highlights the risks of Double Hull in tankers, even if the Limburg explosion was probably due to a terrorist attack. Terrorist attacks seem to be focusing on the loaded waterline area, where the COULOMBI EGG arrangement provides maximum protection. Thus another good reason to opt for the COULOMBI EGG arrangement ... 2012. The concept is approved by all maritime nations except the USA.

Better Tanker Safety at Sea - let the IMO take the lead. The IMO will not do it, but I suggest it anyway.

  The COULOMBI EGG tanker design was developed by Heiwa Co and Mr Anders Björkman, M.Sc., Naval Architect, 1990-1997. Maritime administrations, tanker owners, environmental defence groups, underwriters, P&I Clubs, oil spill prevention interests, media and the public were highly encouraged to support the COULOMBI EGG concept in the joint effort to make oil transport at sea safer and to prevent oil spills and spreading alien marine species around the world. Nobody did it until 2018. So I just struggle on. Nothing wrong with that?


The COULOMBI EGG arrangement was once covered by patents in Japan and South Korea and elsewhere. Now, 2018, anyone is free to use the concept at no cost.